Abstract: A unique assembly is provided having a supporting base. Mounted on or integrally joined to the base is a supporting tray which carries a unitary strippable liner package formed of several tray shaped and separately disposable liquid-impermeable liners, preferably 3-10 mils in thickness, for containing the liquid. The several liners are each easily grasped by the upper liners extending beyond the lower liners. The unitary liner package is held in place by retainer pins and clamped down by an overflow dam. The overflow dam has a pressure edge to seal against the liner package, a grasping ledge to lift it off of the liner package and a rough or uneven surface engaging a similar surface on the supporting tray to ensure continuous clamping pressure. A support rod can be placed transversly in a recess in the overflow dam when coating implements are to be stored in the supporting tray.